In print media production, after a printing or copying device a more or less elaborate post-processing is often implemented for a printing substrate, for example a paper web or paper sheets. The finished printer products are thereby produced from the printing substrate formats used for the printing. Machines of the post-processing can be, for example, cutters, binders, folders, and staplers.
In electrophotographic printing, the toner images (generated on the printing device in the printing device) of the images to be printer are fixed and therewith connected with the printing substrate. This method is known (see WO 01/98840 A2, which is herewith incorporated into the disclosure) and is therefore not explained further here. The fixing can occur in various ways, for example via roller fixing under pressure and heat or via radiation fixing. For the individual techniques, reference is made to the already-cited. WO 01/98840 A2. In the fixing, the printing substrate is thus exposed to heat or pressure, with the consequence that its dampness and sliding properties are negatively influenced. In particular, however, poor sliding properties of the printing substrate can lead to the fixed toner layer being mechanically damaged or smeared in the machines of the post-processing. These damages can lead to accumulations of toner particles at exposed machine parts, which can in turn lead to unwanted toner deposits on the printing substrate. From WO 01/98840 A2 it is known to improve the post-processing of the printing substrate in that the printing substrate is moistened, such that the loss of dampness caused by the printing is compensated for. Water is normally used as a means for moistening.
In general, however, for an acceptable print quality, contamination, particularly on the printing substrate, must be prevented at the machines, in particular for the post-processing. However, it is not sufficient to moisten the printing substrate corresponding to WO 01/98840 A2. Rather, its sliding properties must also be improved.